Lenovo ThinkServer TD200 - Manual (Page 109)

Note: The amount of usable memory is reduced depending on the system
configuration. A certain amount of memory must be reserved for system
resources. To view the total amount of installed memory and the amount of
configured memory, run the Setup Utility. For additional information, see “Using
the Setup Utility” on page 138.
v A minimum of one DIMM must be installed for each microprocessor. For
example, you must install a minimum of two DIMMs if the server has two
microprocessors installed. However, to improve system performance, install a
minimum of three DIMMs for each microprocessor.
v The maximum operating speed of the server is determined by the slowest DIMM
install in the server.
v The server comes with a minimum of two 1 GB DIMMs, installed in slots 3 and 6.
v When you install additional DIMMs in independent mode, install them in the order
shown in the following table to optimize system performance. All three channels
on the memory interface for each microprocessor can be populated in any order
and have no matching requirements.
Table 7. Independent mode DIMM installation sequence
Installed microprocessors DIMM connector population sequence
Microprocessor socket 1 3, 6, 8, 2, 5, 7
Microprocessor socket 2 11, 14, 16, 10, 13, 15
Note: DIMM connectors 1, 4, 9, and 12 are not functional. Do not install DIMMs in these
connectors.
v The server supports memory mirroring (mirroring mode):
– Memory-mirroring mode replicates and stores data on two pairs of DIMMs
within two channels (channels 0 and 1) simultaneously. If a failure occurs, the
memory controller switches from the primary pair of memory DIMMs to the
backup pair of DIMMs. To enable memory mirroring through the Setup Utility,
select System Settings → Memory. For more information, see “Using the
Setup Utility” on page 138. When you use the memory mirroring feature,
consider the following information:
- When you use memory mirroring, you must install a pair of DIMMs at a
time. One DIMM must be in channel 0, and the mirroring DIMM must be in
the same slot in channel 1. The two DIMMs in each pair must be identical
in size, type, and rank (single or dual), and organization, but not in speed.
The channels run at the speed of the slowest DIMM in any of the channels.
- Channel 2, DIMM connectors 7, 8, 15, and 16 are not used in
memory-mirroring mode.
- The maximum available memory is reduced to half of the installed memory
when memory mirroring is enabled. For example, if you install 48 GB of
memory, only 24 GB of addressable memory is available when you use
memory mirroring.
The following table lists the usable DIMM connectors on each memory channel.
Table 8. Connectors on each memory channel
Memory channel DIMM connectors
Channel 0 2, 3, 10, 11
Channel 1 5, 6, 13, 14
Channel 2 7, 8, 15, 16
Chapter 5. Installing optional devices and replacing customer replaceable units 91